White House Press Secretary Sarah Sanders hit back on Wednesday after excerpts were released from a forthcoming book by veteran reporter Bob Woodward detailing an administration beset by infighting.

According to The Washington Post, which obtained an early copy of the book, it portrays a chaotic Trump White House filled with second-guessing by members of Trump’s staff, who repeatedly bad-mouth him behind closed doors.

The book reportedly alleges that Defense Secretary Jim Mattis told associates of the president that he had the understanding of “a fifth- or sixth-grader," and that White House Chief of Staff John Kelly described Trump as “an idiot.”

On "Fox & Friends" on Wednesday, Sanders pushed back on the book's "fictitious claims," noting that it is filled with quotes from anonymous sources, as opposed to having officials on the record.

"Myself, I've been working for the president for three years. And I can tell you, what I've seen so far out of this book is nothing like what's going on in the building me," Sanders said from the White House lawn. "If the things in this book were true, there's no way that this president could be as successful as he's been."

She said that Trump has had the most successful two years of any president in modern history, pointing to tax cuts, victories against ISIS, the remaking of the judiciary and historic deregulation.

She added that Trump is going to continue fulfilling the promises he made to the American people and ticking items off his agenda.

"I do think one thing Bob Woodward got right is that he named the book ‘Fear.' But I think the part he missed was that the fear is coming from the Democrats," Sanders said. "They’re terrified of the fact that this president is so successful and that he's been able to deliver on everything he set out to do and that his policies are actually working."

Watch more from Sanders above, including her thoughts on Democratic lawmakers' "embarrassing" behavior at the Brett Kavanaugh Supreme Court confirmation hearing.

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